A Japanese patent document 1 (i.e., Japanese Patent Laid-Open No. 2011-247185) discloses a fuel injection control device for controlling each of the injectors installed in the cylinders of an internal-combustion engine. The fuel injection control device has a capacitor which supplies a high voltage to an electromagnetic valve and a booster circuit which boosts the battery voltage and charges a capacitor. Further, the fuel injection control device has a discharge switch that is installed in an electric current path which electrically connects the capacitor and the electromagnetic valve. The discharge switch is implemented as a MOSFET. The booster circuit has a first electric current path which connects the battery and the capacitor, and a second electric current path which branches from the first electric current path to lead to a ground. The first electric current path has a booster coil, and the second electric current path has a booster switching element. By switching the booster switching element ON and OFF, the battery voltage is boosted by the booster coil, and the boosted voltage is applied to the capacitor, and the capacitor is charged by the boosted voltage. The boosted voltage or a high voltage charged in the capacitor is applied to the electromagnetic valve of the injector by the turning ON of the discharge switch. Thereby, the electromagnetic valve opens and injection of the fuel is started. After the fuel injection is started, the battery voltage is applied to the electromagnetic valve at a predetermined apply timing (i.e., not from the capacitor but from the other path), for maintaining an open state of the electromagnetic valve and for continuing the fuel injection. Then, after the stoppage of the application of the battery voltage, the electromagnetic valve is closed and the fuel injection is stopped.
In the fuel injection control device disclosed in the patent document 1, in case that a circuit element provided in the electric current path that connects the ground and a boosted voltage path, which is a path for applying the boosted battery voltage to the electromagnetic valve, is short-circuited, an output voltage from the boosted voltage path to the electromagnetic valve becomes substantially the same as a ground voltage. The circuit element in the above case may be, for example, the capacitor of the fuel injection control device or the switching element in the patent document 1. As a result, even when an ON signal is input to the gate of MOSFET which is a discharge switch for the valve opening, MOSFET will not be turned ON and the voltage from the boosted voltage path will not be applied to the electromagnetic valve. In such case, at the predetermined apply timing, the battery voltage is applied from the other path and the electromagnetic valve starts to open at such timing. Therefore, in comparison to a non-short-circuited case, the start of the valve opening is delayed, thereby delaying the start of the fuel injection, which may result in that a preset amount of fuel cannot be injected within a predetermined period.